zEnterprise/zBX for VDI Scalability

Desktop virtualization, referred to as Virtual Desktop Interface (VDI), has long held great promise, and for specialized situations it has delivered big. For general enterprise desktop computing the need is great but the challenges are formidable and the payback is elusive.

IDC has become bullish on VDI payback in the last year. You can see what it says about VDI here and here. In each case it comes up with a nice ROI. DancingDinosaur isn’t going to quibble with IDC, but in talking with very large enterprises they complain that they simply cannot virtualize enough desktops on each server. At best they end up replacing desktop sprawl with desktop server sprawl. An improvement no doubt, but not a big enough gain to undertake what would amount to a massive change management effort if, for instance, you needed to virtualize 40,000 desktops.

Jim Porell, an IBMer familiar to System z people and now Distinguished Engineer, Deputy CTO, IBM Federal Sales, takes a different approach. Using an entry-level z114, a zBX populated with richly configured Hx5 blades, z/VM, and a handful of other components (Raytheon Trusted Computer Solutions’ Trusted Thin Client, CSL-WAVE to manage server instances with a GUI, Virtual Bridges’ VERDE to handle VDI images and provisioning, Intellinx’s zWatch for user activity monitoring, and Vicom Infinity for a variety of simplification software) as well as Tivoli and storage, Porell calculates he can deliver tens of thousands of virtualized desktops for as little as $600 per desktop depending on the mix of user workloads. The user workloads span from minimal browser web surfing to basic MS Office functionality to power users. This is the amortized cost of all the hardware (thin desktop client, z114, zBX, storage), middleware, software, and management across all desktops.

Porell really is talking about a system dubbed Smart Terminal Architecture with Secure Hosts (STASH) and it has been attracting a bit of attention. You can find it here and here (scroll way down to get to the STASH Consortium link). IBM describes it as a new computing environment that offers military grade security from the desktop to the back end. STASH challenges the traditional assumption that greater security and increased performance utilization comes with increased costs. STASH is made up of a multi-functional team across IBM, Raytheon Trusted Computer Solutions, CSL International, Intellinx Software, Virtual Bridges and Vicom Infinity. STASH simplifies the IT environment and saves money while increasing security.

What the zEnterprise brings to this endeavor is massive scalability, reliability, and security. Even the entry level z114 can easily handle dozens of management servers to support the desktops. The zBX packed with 16-core Hx5 blades can handle up to 16 x86 desktops (Windows or Linux) per core and with 28 16-core blades per zBX. When multiplied by four zBX machines per zEnterprise the number of desktops supported really adds up. Porell estimates between 14K and 28K desktops per zEnterprise server.

And if VDI is a new z workload to your data center, which it almost surely would be, you could use the Solution Edition program to buy the z at a deep discount and pick up a zBX also at a discount, although not quite as deep. That should let you drive down the cost per desktop even more.

VMware running View on even the beefiest Intel servers will have trouble matching the scalability, reliability, and security of the zEnterprise/zBX VDI solution with its various STASH piece parts. You would have to engineer in a lot of redundancy just to start. Porell, meanwhile, is talking with clients about deploying half a million virtual desktops or more using the STASH model.

There are other issues to resolve around VDI mainly having to do with change management, though both CSL and Virtual Bridges work to address those problems. With STASH, zEnterprise shops have a good head start on delivering truly scalable, cost-efficient VDI.